State Farm, Geico, Progressive and Allstate — the big four auto insurers in Florida — have been aggressively battling for your business on the airwaves, with each promising lower rates than the other guy.

Auto rates in what is already one of the most expensive states in the country have been on the rise through a steady stream of twice-a-year increases by many insurers since late 2009. All of the big four insurers have been hiking rates.

Take giant State Farm, which insures one out of every five vehicles driven in Florida.

Since November 2009, State Farm has raised its average auto rates four times, between 4.3 and 9 percent each time. That means if you were paying $200 for auto insurance a year and a half ago, the same coverage would cost about $252 today, roughly 26 percent more. Why?

"I can tell you in one word," State Farm spokesman Chris Neal says. "It's PIP. PIP losses continue to accelerate with no end in sight. It's almost the sole reason behind those increases."

PIP, or personal injury protection, covers drivers and passengers hurt in auto accidents. Under the state's no-fault insurance laws, anyone injured is covered for up to $10,000 in medical bills.

The problem: PIP claims have skyrocketed in Florida, along with allegations of PIP fraud. Insurers and the state investigators cite increased reports of staged accidents in which people with minor or no injuries go to medical clinics for treatment and those clinics, in turn, collect up to $10,000 per person in insurance payouts.

A push to clamp down on PIP fraud failed in the Legislature the last session, in part because of concerns that it was overreaching. Personal injury attorneys and some legislators objected that it gave insurers up to three months to pay legitimate claims and that a limit on attorney fees would discourage people from going after insurance companies that deny legitimate claims.

Regardless of what percentage of PIP claims are legitimate, it's clear that claims are on the rise.

A report this year showed that PIP filings rose 28 percent from 2006 to 2010 in Florida. The number of PIP-related lawsuits in which the insurer was the defendant increased by 387 percent in the same four-year period.

In January, economist and Insurance Information Institute president Bob Hartwig said the cost to insurers of covering no-fault fraud is rising by 70 percent annually, and "these costs will eventually be passed along to Florida drivers."

"Eventually" has arrived. In addition to the string of State Farm filings:

• Geico General imposed a pair of rate increases this year, an average 4.5 percent increase effective Jan. 27 and a 5 percent boost effective June 30. Its sister company, Geico Indemnity, imposed rate increases of 4.8 percent and 4.3 percent, respectively, for the same time periods. In a letter to some customers, Geico blamed a continual sharp increase in the number of people claiming injury for every 100 accidents, "although the rate of accidents has remained fairly stable."

• Progressive has raised auto rates about 10 percent since early 2010.

Neal of State Farm said the percentage change reflects the overall increase in the average premium. Collision and comprehensive coverage has actually gotten cheaper, so policies including them may not rise as much. On the other hand, a customer with a bare-bones policy — the state-mandated PIP coverage and property damage liability — could see their premiums go up 20 or 30 percent at renewal time instead of 5 percent, Neal said.

"People that have a lower socioeconomic standing are probably the ones carrying minimum coverage," he said. "So these rate increases hit those that can least afford it."

Newton, who is on the board of the Coalition Against Insurance Fraud, says he has no doubt that PIP costs are rising and that PIP fraud is real. But quantifying fraud has been difficult, he said. An increase in advertising by accident referral firms like 1-800-ASK-GARY has boosted awareness and injury claims, but that doesn't mean many of those claims are not legitimate.

"They say Tampa is now No. 1 in staged accidents," he said, "but they base it on questionable claims. Someone checked a box on a form. There's a perception this may be happening, and perception becomes reality to some extent."

Besides, Newton said, look at how much auto insurers are trying to woo customers. It's obvious it's still a very profitable business.

Stander, whose Property and Casualty Insurers of America represents more than 1,000 insurance companies in Florida, doesn't deny that auto insurance has been a profitable line that everyone wants to dominate.

"I can't watch a 30-minute TV show without seeing an ad for auto insurance," he said, "and at the end of the day, no one is going to sell at a loss."

Nonetheless, he contends that rising PIP costs are starting to take a toll. If rates are left unchecked, he predicts, auto insurers will eventually pull back and the state-run insurer of last resort for auto coverage could see the same explosive growth experienced in the homeowners market. (Citizens Property Insurance has grown to nearly 1.4 million policyholders, the largest property insurer in Florida, as it writes for those who cannot find coverage in the open market.)

Said Stander: "We don't want the auto market to go the way of the homeowners market."

Jeff Harrington can be reached at (727) 893-8242 or harrington@sptimes.com.

Most uninsured motorists

1. Mississippi 28%

2. New Mexico 25.7%

3. Tennessee 23.9%

4. Oklahoma 23.9%

5. Florida 23.5%

50. North Dakota 9.1%

Sources: Insurance Research Council; National Association of Insurance Commissioners

Highest auto insurance expense

Averages, based on 2008 figures:

1. Washington, D.C. $1,126

2. Louisiana $1,105

3. New Jersey $1,081

4. Florida $1,055

5. New York $1,044

50. Indiana $612

Sources: Insurance Research Council; National Association of Insurance Commissioners